The correct answer is: For an African, whether you were sent to the Caribbean or South America, you were now part of the sugar machine.
This is the main idea of the paragraph, in other words, the primary point communicated by the author. It helps giving the overarching idea of the text, it can be described as a brief but all-encompassing summary. In a larger text, with a lot of paragraphs, this main idea is found in the thesis statement. This text is part of the book Sugar Changed the World, I don't know if this main idea is also the thesis statement, it can be just an individual smaller point.
The other options are arguments that support this main idea , they help the author demonstrate that his statement is correct. This evidence helps the reader realize how the Africans were condemned no mattering were they sent them. These other options transmit that confinement feeling; you were forced to drive oxens, to carve twenty-eigth holes an hour, or clear a space five inches deep and five feet square, otherwise you were severely punished.